Grinding-mill



W. G. STEVENSON.

GRINDING MILL. APPLICATION FILEDJUNE 3. I918.

Patented July 19% 3 SHEETS-SHEET l.

W. G. STEVENSON.

GRINDING MILL.

APPLICATION FILED mm: 3. 19:8.

W T/ZQ'ZZZam Q: @762967050/"6 Pmmd y 9 12m,

3 SHEETS-SHEET 2.

to the casting 50 and has the outer flange 54 for confining the annular cylindrical shell 55. The frame 53 has the annular discharge passageway 56 just within the flange 54, the entrance to which passageway is covered by the screen 57. Between the passageway 56 and the hub 51 is laid the grinding plate 58 which is engaged by the grinding rolls. Surrounding the frame 53 and secured thereto is the gear ring 59 with which the driving pinion 60 meshes. This pinion is secured to the lower end of a shaft 61 which extends though the lower and upper bearing frames 62 and 63 supported by the casting 1 1. The shaft at its upper end extends through a housing 64 forming the conical seat 65 for the hub 66 of the bevel gear 67 which is rigidly secured to the shaft. The cover 68 for the housing 64: has the-socket 69 for receiving the upper end of the shaft. Extending laterally into the housing 641 and journaled in the bearing 70 thereon is the transmission shaft 71 which within the housing has secured thereto a beveled pinion 72 which meshes with the gear 67. ,The outer end of the shaft section 71 is journaled in the bearing 7 3 and terminates in a coupling member 74 which cooperates with the coupling member 75 secured to the shaft of the motor M mounted on the casting 14. The motor thus provides the driving power for turning the pan structure.

Describing now the grinding roll mechanism, two rolls 76 and 77 are shown. As best shown in Fig. 1, each roll is secured to a short shaft 7 8 by means of the split rings 7 9 and 80 of conical cross-section, the bolts 81 drawing the rings into wedging engagement between the conical sections of the wheel and shaft respectively. Flanges or end plates 82 and 83 receive the shafts and engage against the sides of the roll and have pockets 84 for receiving the ends of the bolts. The outer ends of the shaft are received by rectangular bearing caps or frames 85 and 86. These bearing caps extend into the rectangular frame enlargements87 and 88 in each of which are the opposed guide blocks or liners 89 and 90 which engage the sides of the bearing caps and prevent them from turning axially. Lateral displacement of the bearing caps is prevented by the cylindrical lugs 91 and 92 thereon which extend into the vertical grooves 93 and 9 1 formed in the liner blocks, the liner blocks being held in position by bolts 95. The grinder wheels rest on the plate 58 of the pan structure and crush and grind the material charged into the machine as the pan structure is rotated, the rolls being free to move vertically. In order to prevent the heavy rolls from dropping in case the pan structure should break or fall, U-straps 96 extend around the sides and bottom of the frame enlargements containing the bearing caps, and these straps may be supported by the same bolts which hold the liner blocks in position. It, now, the pan structure is dropped or should break, the rolls will be received and sup ported by the straps.

The openings 97 and 98 in the top of the casting 14 through which the rolls extend are provided with removable covers 99 and 100, respectively, and the upper ends of the various frame enlargements in which the roller bearings are housed have a ltll'lUVillJlC cover 101. By removal of the covers the rolls and bearing parts are readily accessi ble and when the covers are in place these parts are amply protected against dust and dirt.

Scraper structures are provided for guid ing the material into the path of the rolls. Two such scraper structures are shown, each comprising a frame body 102 supported by means of a bracket 103 fastened to the bot tom of the casting 14; by bolts 104. The body part of each scraper supports the outer, inner and intermediate blades 105, 106 and 107, respectively. These blades are supported by bolts and in order to provide for adjusting the blades the bolt holes 108 in the body are elongated in one direction and the bolt holes 109 in the various ilades elongated in the opposite direction. The bolt holes are also so situated that the blades can be reversed. For example, on the outer blade 105 the lower outer corner will wear most rapidly, and after such wear the blade can be turned around to present another corner. Likewise, the inner and intermediate blades can be reversed after they have become worn along one edge or corner. To assist in holding the blade structures rigidly in position the outer ends of their bodies are connected by a turn buckle link 110 with the frame 14.

The scraper members are inclined. in a direction to shift the material to be ground into the path of the rolls, as shown in Fig. 2, the arrow indicating the direction of rotation of the pan structure. The material is fed onto the pan structure by means of a chute 111 leading to the passageway 112 in the frame 14 which opens at its lower end above the pan structure, and as the pan. structure rotates the material will be thrown outwardly by centrifugal force onto the screens, and the material which is already sufliciently tine will fall through the screen holes into the pit 10. The larger material will. be deflected inwardly by the scraper blades and directed to the rolls to be there ground, and this guiding action and the centrifugal force cooperate until all the material has been ground and discharged through the screens.

Vhere the material is ground fine considerable dust will be raised but with my iinproved structure and arrangement all the bearings; parts are well protected. The part of the pit not covered over by the f 'aine 1 1 is covered by the plates 113 and 11 i. lhese plates and the various caps and covers for the bearing parts are readily removable so that inspection and repairs can be quickly and readily made. This covering; of all the parts insures safety as during operation of the machine it will be inipossible for any thing to fall into the machinery or for the operators to be injured. The machine is well balanced and efficient.

it do not desire to be hunted to the exact construction and arrangement shown and described as changes are no doubt possible which would still come within the scope of the invention.

1 claim as follows: 111 a grlndlng machine of the class described, the combination of a pit, a support ing frame bridging over said pit, a pan structure supported on said frame for axial rotation, said frame having vertical passageways therethrough, grinding rolls pro jecting downwardly through said passageways into engagement with the pan structure, vertical guide grooves in said frame for each passageway, journal boxes slidable in said gui le grooves, and a shaft for each roll having its ends extending into said journal boxes whereby said rolls may freely rotate and shift bodily vertically during operation of the machine, said guide grooves being open at the top whereby each roll together with its shaft and journal boxes may be lifted through said passage ways and removed from the machine.

In witness whereof I hereunto subscribe my name this 29th day of May, A. D. 1918.

WILLIAM G. STEVENSON. 

